Techniques for controlling operation of the drill driver while driving a fastener are readily known. For example, the drill driver may implement an automated fastener setting technique which determines when a fastener reaches a desired stopping position in the workpiece and stops operation of the tool in response thereto. The desired stopping position may be detected, for example by monitoring the motor current behavior or change therein. Sensor signals indicative of the motor current, however, tend to be noisy and thereby lead to inaccuracies in the detection of the desired stopping position. Therefore, it is desirable to develop improved fastener setting techniques that are more immune to noise as compared to conventional methods.
When implementing an automated fastener setting method, it is desirable to avoid false triggers of the electronic clutch. False triggers may occur, for example when the drill bit slips and becomes disengaged from the fastener being driven the by the tool (also referred to as a “cam out” condition). When the drill bit disengages the fastener, the load of the motor will be absent and the motor current will drop rapidly until the drill bit re-engages the fastener. Once the drill bit re-engages the fastener, the motor current will rise up to the proper level. The sudden increase in the motor current may be used to trigger the electronic clutch and thus can cause a false trigger of the electronic clutch following a cam out condition. Therefore, it is also desirable that an automated fastener setting method avoid such false triggers of the clutch.
This section provides background information related to the present disclosure which is not necessarily prior art.